The LGA is basically the number of pins on the CPU/Motherboard socket. Understandably, you cannot put a 1155 pin CPU in a 1366 pin motherboard.

If you want to stick with the X58 Sabertooth motherboard, you'll want a Core i7-930 or 950. If you want to stick with the Core i5-2500K, you'll want either a P67 or a Z68 motherboard, as H61 and H67 motherboards do not allow significant overclocking. P67 cannot use the intergrated Intel GMA HD3000 graphics core, but H6x and Z68 motherboards can, and Z68 motherboards have fancy features that switch between the Intel GMA graphics and a graphics card depending on how demanding the tasks you're running are (e.g. for games, it'll switch to the more powerful graphics card).

Here's an ASUS P67 Sabertooth if you really wanted a Sabertooth motherboard that has LGA 1155. It's been reviewed as the best gaming motherboard by CustomPC Magazine, although it doesn't overclock as well as an Asus Maximus IV Extreme or a MSI P67A-GD53 (B3). CPC recommend the MSI motherboard for new computers (because the Maximus is much more expensive).

That combo won't work, the mobo is an 1366 chipset and you're trying to put a sandy vagina in it. SB is 1155. That also means that they won't fit in the first gen i3/i5/i7 1156 motherboards.

May I recommend the P8P67 Pro? It is similar to the Sabertooth, minus the gimmick TUF armor.

The Pro is amazing for overclocking, which I know you'll be doing seeing as you're getting a 2500k. I got the Deluxe, but only because when I was in the market for a B3 motherboard, only the Deluxe was in stock. The two front USB 3.0 ports are a nice bonus, but not worth the difference.

Quoted from Originality:

P67 cannot use the intergrated Intel GMA HD3000 graphics core, but H6x and Z68 motherboards can

Click to expand...

Isn't it the other way around? I thought H67 couldn't use integrated graphics, but Z68 and P67 could.

Either way, nobody should ever have to use the terrible onboard Intel graphics